Disease and Yield Responses to Fungicides Among Peanut Cultivars Differing in Reaction to Sclerotinia Blight1

1996 ◽  
Vol 23 (2) ◽  
pp. 81-85 ◽  
Author(s):  
J. P. Damicone ◽  
K. E. Jackson

Abstract Peanut cultivars with different disease reactions to Sclerotinia blight received a variable number of applications of iprodione at 1.12 kg/ha or fluazinam at 0.56 kg/ha to determine the most efficient management program. Significant (P ≤ 0.05) cultivar x treatment interactions occurred for each fungicide. In two trials with iprodione, two applications reduced disease incidence for the susceptible cultivar Okrun from 62 to 27% as compared to the control, and increased yield from 2034 to 2581 kg/ha. Three applications did not improve disease control or increase yield as compared to two applications. Iprodione did not affect disease incidence or yields of the moderately resistant cultivar Spanco (9%, 2475 kg/ha) or the resistant cultivar Tamspan 90 (3%, 2903 kg/ha). In three other trials, fluazinam reduced disease incidence in one or more trials and increased yields across trials for all cultivars. Two applications provided the best disease control for Okrun as disease incidence was reduced from 77 to 22%. However, the increase in yield for one (1034 kg/ha) and two (1415 kg/ha) applications did not differ. Reductions in disease incidence with fluazinam varied for Spanco and Tamspan 90, and the yield increase was less than for Okrun. Two applications for Spanco reduced disease incidence from 17 to 7% and increased yield from 2900 to 3484 kg/ha. One application to Tamspan 90 reduced disease incidence from 10 to 5% and increased yield from 3348 to 3891 kg/ha. Tamspan 90 had the highest yield in all trials regardless of fungicide treatment.

2001 ◽  
Vol 28 (1) ◽  
pp. 28-33 ◽  
Author(s):  
J. P. Damicone ◽  
K. E. Jackson

Abstract Two trials with iprodione and three trials with fluazinam were conducted to assess the effects of application method and rate on the control of Sclerotinia blight of peanut with fungicide. In order to concentrate the fungicides near the crown area where the disease causes the most damage, applications were made through a canopy opener with a single nozzle centered over the row to achieve a 30.5-cm-wide band (canopy opener), and through a single nozzle centered over the row to achieve a 46-cm-wide band (band). Broadcast applications were compared to these methods at rates of 0, 0.28, 0.56, and 1.12 kg/ha on the susceptible cultivar Okrun. Sclerotinia blight was severe, with > 70% disease incidence and < 2000 kg/ha yield for the untreated controls in each trial. Linear reductions in area under the disease progress curve (AUDPC), but not final disease incidence, with iprodione rate were significant (P < 0.05) for all methods of application. However, the rate of decrease did not differ among application methods. Linear increases in yield with rate of iprodione were greater for canopy opener compared to the band or broadcast applications. Only a 50% reduction in AUDPC and a maximum yield of < 2700 kg/ha was achieved with iprodione using the best method. At the maximum rate of 1.12 kg/ha, fluazinam provided > 75% disease control and > 4000 kg/ha yield for all application methods. Differences in disease control and yield among application methods only occurred at the 0.28 and 0.56 kg/ha rates of fluazinam. Reductions in AUDPC with fluazinam rate were quadratic for all application methods, but AUDPC values were less for the canopy opener and band methods at 0.28 and 0.56 kg/ha compared to the broadcast methods. The yield response to rate for broadcast applications of fluazinam was linear. However, predicted yield responses to fluazinam rate were quadratic for the band and canopy opener methods and approached the maximum response at 0.84 kg/ha. Targeting fungicide applications using the band and/or canopy opener methods was beneficial for fluazinam at reduced rates. Disease control with iprodione was not adequate regardless of application method.


2017 ◽  
Vol 44 (1) ◽  
pp. 42-46 ◽  
Author(s):  
W. D. Branch ◽  
S. M. Fletcher

ABSTRACT With increasing production cost, southeast U.S. peanut (Arachis hypogaea L.) growers are continually seeking to lower inputs to enhance economical return and sustainability of their farming operation. Utilization of peanut cultivars with the best combination of disease resistance, drought tolerance, and greatest dollar value return would be beneficial. Fifteen peanut cultivars were evaluated for 5-years (2011–15) and seventeen cultivars were evaluated for 4-years (2012–15) with minimum inputs and without irrigation at two locations in Georgia. Each year, minimum inputs for disease control included only three fungicide sprays at recommended rates on a 28 d schedule beginning 37 d after planting. No insecticide, nematocides, miticides, or irrigation were applied during the growing seasons each year. ‘Georgia-06G', ‘Georgia-12Y', ‘Georgia-13M', ‘Georgia-14N', and Florida-EP ‘113’ had the lowest TSWV and total disease incidence (disease resistance) among the ten runner-type cultivars for both Georgia locations; whereas, ‘Bailey', ‘Georgia-08V', and ‘Georgia-11J' had the least disease incidence among the five virginia-type cultivars. Similarly, Georgia-13M, Georgia-06G, and Georgia-12Y had the greatest gross dollar value return per hectare (drought tolerance) among the runner-types; whereas, Georgia-08V and Georgia-11J had the greatest dollar values per hectare among the virginia-type cultivars at both Georgia locations in this four and five-year study, respectively.


1973 ◽  
Vol 9 (1) ◽  
pp. 73-82
Author(s):  
G. L. James

SUMMARYSugarcane yields and smut incidence levels were observed in three successive crops. The effect of pathogen upon host was primarily one of stress, as smut infection was shown to increase sucrose content of cane whilst depressing yields in tonnes of cane per ha. Where infection levels were high, roguing was shown to increase disease incidence. However, smut whip removal was confirmed as the best roguing treatment for commercial fields. Disease control and yield responses related to roguing effort were much better in NCo 376 than NCo 310; and, therefore, continued cultivation of NCo 310 fields with high smut incidence was concluded to be a major hazard to the industry.


2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Jason E. Woodward ◽  
Scott A. Russell ◽  
Michael R. Baring ◽  
John M. Cason ◽  
Todd A. Baughman

Field studies were conducted from 2007 to 2010 to evaluate the response of peanut cultivars to different fungicides, application timings, and methods. Overall, fungicides reduced Sclerotinia blight incidence and increased pod yields when applied to susceptible and partially resistant cultivars. Disease suppression was greater when full fungicide rates were applied preventatively; however, yields between fungicide treated plots were similar. Lower levels of disease and higher yields were achieved with the partially resistant cultivar Tamrun OL07 compared to the susceptible cultivars Flavor Runner 458 and Tamrun OL 02. Despite possessing improved resistance Tamrun OL07 responded to all fungicide applications. While similar levels of disease control were achieved with broadcast or banded applications made during the day or at night, the yield response for the different application methods was inconsistent among years. A negative relationship (slope = −73.8;R2=0.73;P<0.01) was observed between final disease incidence ratings and yield data from studies where a fungicide response was observed. These studies suggest that both boscalid and fluazinam are effective at controlling Sclerotinia blight in peanuts. Alternative management strategies such as nighttime and banded applications could allow for lower fungicide rates to be used; however, additional studies are warranted.


2017 ◽  
Vol 44 (2) ◽  
pp. 100-110 ◽  
Author(s):  
H.L. Mehl

ABSTRACT As new cultivars are developed and released by peanut breeding programs, their levels of tolerance to common diseases and the overall profitability of production needs to be determined. Virginia-type peanut cultivars were evaluated for disease resistance/tolerance, yield, and quality when grown under different fungicide programs and in locations varying in disease pressure. Cultivars included a disease susceptible (CHAMPS) and tolerant (Bailey) cultivar and two new high-oleic cultivars, Sullivan and Wynne. Fungicide programs consisted of a leaf spot program, a leaf spot plus Cylindrocladium black rot (CBR) program, a leaf spot plus Sclerotinia blight program, or an untreated check. Cultivars and fungicide programs were arranged in a randomized split-plot design with fungicide treatments in 16-row main plots and cultivars in 4-row subplots. Disease incidence and severity varied among growing seasons and the five fields where experiments were conducted. Overall, Sullivan had good leaf spot tolerance and both Sullivan and Bailey had Sclerotinia and CBR tolerance. All cultivars yielded well in the absence of disease pressure, but Sullivan was consistently the highest yielding cultivar. Grade characteristics varied among cultivars, but while fungicide treatments impacted yield, they had little effect on grade. Net value and profitability of different fungicide programs varied by experiment, but overall Sullivan had the highest net value regardless of fungicide program. Due to slightly higher disease tolerance compared to Bailey, good agronomic characteristics, high yield and quality under a variety of growing environments, and the presence of the high-oleic trait, Sullivan is an excellent cultivar for Virginia-type peanut production in the Virginia-Carolina region.


2013 ◽  
Vol 368 (1623) ◽  
pp. 20120148 ◽  
Author(s):  
Diane S. Saint-Victor ◽  
Saad B. Omer

As multiple papers within this special issue illustrate, the dynamics of disease eradication are different from disease control. When it comes to disease eradication, ‘the last mile is longest’. For social and ecological reasons such as vaccine refusal, further ending incidence of a disease when it has reached low levels is frequently complex. Issues of non-compliance within a target population often influence the outcome of disease eradication efforts. Past eradication efforts confronted such obstacles towards the tail end of the campaign, when disease incidence was lowest. This article provides a comparison of non-compliance within polio, measles and smallpox campaigns, demonstrating the tendency of vaccine refusal to rise as disease incidence falls. In order to overcome one of the most intractable challenges to eradication, future disease eradication efforts must prioritize vaccine refusal from the start, i.e. ‘walk the last mile first’.


2005 ◽  
Vol 32 (10) ◽  
pp. 945 ◽  
Author(s):  
Thomas R. Sinclair ◽  
Graeme L. Hammer ◽  
Erik J. van Oosterom

Limitations on maximum transpiration rates, which are commonly observed as midday stomatal closure, have been observed even under well-watered conditions. Such limitations may be caused by restricted hydraulic conductance in the plant or by limited supply of water to the plant from uptake by the roots. This behaviour would have the consequences of limiting photosynthetic rate, increasing transpiration efficiency, and conserving soil water. A key question is whether the conservation of water will be rewarded by sustained growth during seed fill and increased grain yield. This simulation analysis was undertaken to examine consequences on sorghum yield over several years when maximum transpiration rate was imposed in a model. Yields were simulated at four locations in the sorghum-growing area of Australia for 115 seasons at each location. Mean yield was increased slightly (5–7%) by setting maximum transpiration rate at 0.4 mm h–1. However, the yield increase was mainly in the dry, low-yielding years in which growers may be more economically vulnerable. In years with yield less than ∼450 g m–2, the maximum transpiration rate trait resulted in yield increases of 9–13%. At higher yield levels, decreased yields were simulated. The yield responses to restricted maximum transpiration rate were associated with an increase in efficiency of water use. This arose because transpiration was reduced at times of the day when atmospheric demand was greatest. Depending on the risk attitude of growers, incorporation of a maximum transpiration rate trait in sorghum cultivars could be desirable to increase yields in dry years and improve water use efficiency and crop yield stability.


2018 ◽  
Vol 10 (10) ◽  
pp. 513
Author(s):  
M. C. Kottayi ◽  
D. D. Saoji ◽  
S. E. Pawar ◽  
A. D. Choudhary

The disease incidence of Cercosporidium personatum in field was analysed in the hybridized population derived from the resistant mutant lines of the cultivar ICGV-87304 and TAG-24 &amp; TG-26. Reciprocal crosses were performed using the same parents. The comparison of disease incidence in hybridized population was made with resistant cultivar Girnar-1. Susceptible parents TAG-24 and TG-26 showed disease incidence of 14.08 and 16.40%, respectively while Girnar-1 and the resistant mutant parents showed percentage infection ranging from 0.06-0.96%. The plants raised from the hybridized population showed the percent infection ranging from 0.01 to 0.02 %.


1980 ◽  
Vol 60 (3) ◽  
pp. 841-846 ◽  
Author(s):  
R. S. FULKERSON

The effect of post-harvest stubble removal dates upon the succeeding year’s seed yield of timothy (Phleum pratense L. ’Climax’), orchardgrass (Dactylis glomerata L. ’Frode’), and smooth bromegrass (Bromus inermis Leyss. ’Saratoga’) was investigated over four harvest years. The stubble was removed each year on 15 Aug., 15 Sept., 15 Oct., 15 Aug. and 15 Sept., 10 Apr., or left uncut. The experiments were conducted under conditions of adequate soil fertility. No stubble removal treatments increased the seed production of timothy. Orchardgrass seed yields were increased by all fall removal treatments but responded best to the 15 Aug. removal. Bromegrass responded to all stubble removal treatments but produced its highest seed yield from the 15 Oct. treatment. Seed yields declined with successive years until year 5 when timothy, and particularly orchardgrass, produced a yield increase. The interaction for years × stubble removal dates was significant only for bromegrass seed yield. Seed yield was highly correlated with panicle number in all species, with weight of seed in 25 panicles in timothy and bromegrass, and with 200-seed weight in timothy.


Plant Disease ◽  
2019 ◽  
Vol 103 (5) ◽  
pp. 938-943 ◽  
Author(s):  
A. S. Grode ◽  
E. Brisco-McCann ◽  
P. Wiriyajitsonboom ◽  
M. K. Hausbeck ◽  
Z. Szendrei

Onion thrips (Thrips tabaci) is a major insect pest of onion and it has been identified as a likely vector of Pantoea agglomerans (bacterial stalk and leaf necrosis), a relatively new pathogen to Michigan’s onion industry. Our objective was to develop an integrated insect and disease management program by examining the efficacy of bactericides and insecticides alone and in combination to limit bacterial stalk and leaf necrosis caused by P. agglomerans. We also examined the association of onion thrips and disease incidence in the field, because thrips are known to transmit this pathogen. In the pesticide trial, insecticides reduced both thrips abundance and bacterial stalk and leaf necrosis incidence whereas bactericides alone did not reduce disease severity. Positive correlations among thrips population density, numbers of thrips positive for P. agglomerans, and bacterial stalk and leaf necrosis incidence in onion fields were determined. This study suggests that onion thrips feeding can facilitate the development of bacterial stalk and leaf necrosis in Michigan’s commercial onion fields, and results from the pesticide trials indicate that thrips feeding damage is positively correlated with disease incidence. Therefore, in order to reduce bacterial stalk and leaf necrosis incidence in onion, management efforts should include reducing onion thrips populations through the use of insecticides and other cultural practices.


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